Capillarity of Molten Bodies. 



87 



7, To obtain drops of tin and selenium, these substances were 

 molten in glass tubes, the lower part of which was funnel-shaped, 

 ending in a thin vertical pipe. The part of this pipette-shaped 

 pipe which was cut off by the glass-knife was used to determine 

 the inner or outer diameter by means of microscope and eyepiece- 

 micrometer. Figs. 2 and 3 show the drop attached to the outer 

 and inner circumference. Determinations in which the drops 

 had formed partly on the inside, partly on the outside (fig. 4), 

 Fig. 2. Fig. 3. Fig. 4. 



Fig. 5. 



or where the outer glass wall was wetted 

 by the drops (fig. 5), were rejected. The 

 drops fell into a fiat porcelain saucer filled 

 with water, or which was simply kept 

 cold. T took great pains to see that the 

 drops were formed as slowly as possible. 

 They followed each other usually so much 

 the more slowly the more the cooling- 

 down progressed. The last drop which 

 fell before complete solidification was 

 heavier than that preceding, which was 

 again heavier than that before it, and so 

 on; so that the capillarity-constant in- 

 creases with diminishing temperature. 

 The difference, however, is insignificant, 

 and in some cases I have given means 

 collected from these last drops. Strictly 

 speaking, the last drop determines the 

 capillarity-constant in the neighbourhood 

 of the melting-point. From the upper 

 part of the pipette-shaped vessel a piece of india-rubber tubing- 

 went to the mouth, which made it easy to regulate the speed 

 of the issuing fluid. 



The determinations for zincweve made in the same way; but, 

 in consequence of the higher melting-point, it was found more 



